Pathologists across the country are calling for better access to blood tests to identify which patients are vulnerable to life-threatening reactions to medications such as codeine and chemotherapy.
Cancer patient Jennifer Kohne wasn’t able to properly metabolise her chemotherapy tablets when going through her bowel cancer treatment.
The drugs sent her body into a toxic overdrive.
“I started developing severe abdominal pain, the diarrhoea was so bad, the nausea became quite bad,” Kohne said.
A DPYD test revealed that she had a genetic variant that caused her to react badly to the common chemotherapy medication Capecitabine.
Medical Oncologist Dr Cassandra White says Kohne isn’t the only patient to have a bad reaction to chemo.
“One per cent of patients die from side-effects relating to their chemotherapy, not related to their cancer,” White said.
The Royal College of Pathologists is calling for the test for which patients are vulnerable to life-threatening reactions to medications, called pharmacogenomic testing, to be better funded.
The college has two applications before the Medical Benefits Advisory Committee to consider rebates for two genetic tests for chemotherapy and anti-seizure medication.
White said pre-exposure DPYD testing was already standard practice across Europe and within the UK.
Professor Luke Hesson from the RCPA’s Pharmacogenomic Advisory Committee said preventing patients from going into hospital also made economic sense.
“These tests range in cost from around $80 to $200 … hospitalisation due to these adverse reactions can cost tens of thousands of dollars,” Hesson said.
“For a test of $160 versus a hospitalisation of a patient of at least $30,000 there’s a clear cost benefit to funding this type of testing.
“There are around 17,000 patients in Australia that receive fluorouracil chemotherapy … around 30 per cent of patients who are treated with fluorouracil will develop toxicity.
“Around half of those are due to DPD deficiency, the enzyme that actually metabolises that drug in the body.”
The RCPA has listed 35 medications where pharmacogenomic testing can be performed to predict side effects or therapy failure.
The drugs include common antidepressants like Amitriptyline, Nortriptyline, Imipramine, and others.
Other drugs on the list include Allopurinol which is used to treat gout as well as codeine and Tramadol for pain relief.
Neurological medications Oxcarbazepine, Phenytoin and Carbamazepine are also on the list, as well as cholesterol-lowering drugs including Atorvastatin, Pravastatin, and Rosuvastatin, as well as blood thinners Clopidogrel, and Warfarin.
“People can be walking around the community and not know they may be carrying one of these variants,” White said.
Pre-exposure testing is recommended by experts and international regulatory bodies for 12 of the 35 medications.
Oncologists and psychiatrists are leading the way in Australia in adopting the testing regime.
